I owe arrears and was just recently approved for disability going back 3 years will the child support agency remove those 3 years what do i do?

The only person who can forgive the child support arrears you owe is the person you owe the money to, presumably your ex. If they were on asssitance, there may be money also owed as part of the arrears to the state. The state can negotiate that portion of the arrears and compromise with you, but any balacne owed to your ex spouse or the parent of your child, is an issue between you and them. You can also try to compromise the amount by offering to pay a limited lump sum payment to waive the balance.